So I'm checking out the changes related to the latest backbone/underscore version. Prior I have a project running with BB 0.5.2 and underscore 1.1.7. I'm noticing something strange with regards to defining a template property within a view in the new version, which gives me reservations in going forward with upgrading.
In my current version I would define a view as such:
var MyView = Backbone.View.extend({
template: _.template($('#exampleTemplate').html()),
initialize: function() {...},
render: function() { $(this.el).html(this.template(someObjectParam)); },
});
However, if I attempt to work in the same manner, using a simplified todo clone attempt as an example, I setup an html with an inline script template as such:
<script>
$(document).ready(function() {
app.init();
});
</script>
<script type="text/template" id="itemViewTemplate">
<div class="item">
<input type="checkbox" name="isComplete" value="<%= item.value %>"/>
<span class="description"><%= item.description %></span>
</div>
</script>
In my included JS file I have:
var ItemView = Backbone.View.extend({
el: 'body',
// Below causes error in underscore template, as the jquery object .html() call
// returns null. Commenting will allow script to work as expected.
templateProp: _.template($('#itemViewTemplate').html()),
initialize: function() {
// Same call to retrieve template html, returns expected template content.
console.log($('#itemViewTemplate').html());
// Defining view template property inside here and calling it,
// properly renders.
this.template = _.template($('#itemViewTemplate').html());
this.$el.html(this.template({item: {value: 1, description: 'Something'}}));
},
});
var app = {
init: function() {
console.log('Fire up the app');
var itemView = new ItemView();
}
}
So I'm left confused as to why defining the template property directly causes the call to retrieve the template html to return a null value, thus breaking the attempt to define an underscore template object (mouthful). However, if the definition is done within the initialize function, the call to retrieve the template html properly finds the template so its contents can be passed to the underscore template. Anyone see what I'm potentially missing?
Thanks in advance!
If this:
var ItemView = Backbone.View.extend({
//...
templateProp: _.template($('#itemViewTemplate').html()),
//...
});
is failing because $('#itemViewTemplate').html() is null, then you have a simple timing problem: you're trying to read the content of #itemViewTemplate before it exists. Your old version should suffer from exactly the same problem.
Either make sure everything is loaded in the right order (i.e. your views after your template <script>s) or compile the template in your view's initialize. You can check for the templateProp in your view's prototype and only compile it on first use if you want:
initialize: function() {
if(!this.constructor.prototype.template)
this.constructor.prototype.template = _.template($('#itemViewTemplate').html());
//...
}
Demo: http://jsfiddle.net/ambiguous/HmP8U/
Related
I am using Backbone and Underscore to create a small test site.
I am compiling all my html template files into one JST javascript file as suggested here and here.
It isn't however very obvious how to use this with template files. I have tried this:
App.HeaderView = Backbone.View.extend({
el: '#headerContent',
template: JST['header.html'](),
//template: window["JST"]["header.html"],
//template: _.template("<h1>Some text</h1>"),
initialize: function () {
this.render();
},
render: function() {
//var html = this.template();
//// Append the result to the view's element.
//$(this.el).append(html);
this.$el.html(this.template());
return this; // enable chained calls
}
});
The error I get is JST.header.html is not a function.
(The final commented out bit works by the way template: _.template("<h1>Some text</h1>") so I know the problem isn't with anything else).
It might be because I am using browserify (so have tried 'requiring' the file), but I have tried several different ways of 'including' the template file, including adding it directly:
<script src="templates/_templates.js"></script>
<script src="js/functions.js"></script>
</body>
</html>
Any ideas what needs to be done to get this to work?
On line 3 you don't want to invoke the template, rather just use:
template: JST['header.html'].
Currently you're setting template to equal the return value of the function and then trying to invoke that return value instead of the actual function, so it is raising a "is not a function" error.
I 'm trying to develop a simple RSS app using backbone.js. I 'm using this backbone.js tutorial. I 'm getting the following error, on line 2(template), when defining the template.
Can someone also tell me why is tagName: "li" defined in the tutorial?
uncaught TypeError: Cannot call method 'replace' of undefined
backbone.js
Javscript
window.SourceListView = Backbone.View.extend({
tagName:"li",
template: _.template($('#tmpl_sourcelist').html()),
initialize:function () {
this.model.bind("change", this.render, this);
this.model.bind("destroy", this.close, this);
},
render:function (eventName) {
$(this.$el).html(this.template(this.model.toJSON()));
return this;
},
close:function () {
$(this.el).unbind();
$(this.el).remove();
}
});
HTML
<script type="text/template" id="tmpl_sourcelist">
<div id="source">
<a href='#Source/<%=id%>'<%=name%></a>
</div>
</script>
thanks
You're getting your error right here:
template: _.template($('#tmpl_sourcelist').html()),
Part of _.template's internals involves calling String#replace on the uncompiled template text on the way to producing the compiled template function. That particular error usually means that you're effectively saying this:
_.template(undefined)
That can happen if there is no #tmpl_sourcelist in the DOM when you say $('#tmpl_sourcelist').html().
There are a few simple solutions:
Adjust your <script> order so that your #tmpl_sourcelist comes before you try to load your view.
Create the compiled template function in your view's initialize instead of in the view's "class" definition:
window.SourceListView = Backbone.View.extend({
tagName:"li",
initialize:function () {
this.template = _.template($('#tmpl_sourcelist').html());
//...
As far as tagName goes, the fine manual has this to say:
el view.el
[...] this.el is created from the view's tagName, className, id and attributes properties, if specified. If not, el is an empty div.
So having this in your view:
tagName: 'li'
means that Backbone will automatically create a new <li> element as your view's el.
I'm trying to use a simple inline underscore.js template with backbone, and pulling the template from a <script> tag via jQuery's html() method.
The page is supposed to render multiple Recipe callouts for each returned by the Recipe Model. It works on the first thumbnail, but on the second, it seems the <script> tag has been removed from the DOM, so underscore fails to render it and bails with str is null on line 913
For the template, I have
<script type="text/html" id="user-recipe-rated-template">
<div class="user-recipe-rated">
<a class="thumb" href="<%= href %>"></a>
<p><%= title %></p>
</div>
</script>
And the backbone view looks like:
var UserRecipeView = Backbone.View.extend({
initialize : function() {
this.template = _.template($("#user-recipe-rated-template").html());
},
render : function()
{
this.el = this.template({
title: this.model.get("Title"),
href: '#'+this.model.get('UserContentId'),
image_src: this.model.get('ThumbnailSrc')
});
return this;
}
});
So, what I am seeing is that $("#user-recipe-rated-template") exists on the first thumbnail and all is well. On the second, it returns an empty array and underscore can't proceed.
I've trying memoizing the string of html and such, and that might work, but it seems there should be a cleaner way of doing this. What am I doing wrong?
(I'd like to use templates inlined as opposed to external JST for now to keep things simple - it seems nicer to have the template embedded in the page near where it will be loaded when the data comes in)
I have model Post and collection Posts. And want to make form with list of all post in <select id="multi" multiple="multiple">. So i have to make a PostView render inside my #multi with just this template:
<option value=""><%= title %></option>
But finally I get it wrapped with div. Is there any solution for not wrapping this template with <div>?
If you don't define an el (or tagName) for the view (in the class or during instantiation) the view will be placed inside a div tag. http://documentcloud.github.com/backbone/#View-el
var PostView = Backbone.View.extend({
tagName: 'option'
});
UPDATE
Starting v0.9.0, Backbone has view.setElement(element) to get this done.
var PostView = Backbone.View.extend({
initialize: function() {
var template = _.template('<option value=""><%= title %></option>');
var html = template({title: 'post'});
this.setElement(html);
}
});
If you don't want to have the view wrap your HTML, you'll have to do a few things:
Replace this.el entirely
Call delegateEvents on the new el
render: function(){
var html = "some foo";
this.el = html;
this.delegateEvents(this.events);
}
Since Backbone generates a div or other tag (based on your tagName setting for the view), you have to replace it entirely. That's easy to do. When you do that, though, you lose your declared events because Backbone uses jQuery's delegate under the hood to wire them up. To re-enable your declared events, call delegateEvents and pass in your events declarations.
The result is that your view.el will be the <option> tag that you want, and nothing more.
In version 0.9.0, Backbone introduced view.setElement(element) to handle this operation.
From the backbone documentation:
All views have a DOM element at all times (the el property), whether they've already been inserted into the page or not.
I have following very simple javascript file:
CBBItem = Backbone.Model.extend(
{
});
CBBTrackItem = Backbone.View.extend(
{
template: _.template("<span><%= title %></span>"),
initialize: function()
{
_.bindAll(this, "render");
},
render: function()
{
$(this.el).html(this.template(this.model.toJSON()));
return this;
}
});
And a html page like this:
<script type="text/javascript">
$(function()
{
var itm1 = new CBBItem({ title: 'track 1'});
var itmUI1 = new CBBTrackItem({ model: itm1, id: "kzl" });
itmUI1.render();
});
</script>
<body>
<div id="kzl"></div>
</body>
My view item doesn't want to render although there is a created div on the page. I can trick the situation in many ways. For example doing something like this
var itm1 = new CBBItem({ title: 'track 1'});
var itmUI1 = new CBBTrackItem({ model: itm1, id: "big_kzl" });
$(itmUI1.render().el).appendTo("#kzl");
But, why is the main case not working?
Here's one possibility: you aren't setting the el for the view, so it doesn't know what to do with your template. Could you modify your view-calling code to look like this?
var itmUI1 = new CBBTrackItem({
model: itm1,
id: "big_kz1",
el: "#kz1"
});
itmUT1.render();
Alternatively, you could set the el value within the initialize of the view if the value never varies. The advantage to doing so is that callers of the view don't have to know this information and thus the view is more self-contained.
If the document already has the element you want to use as el for a particular view, you have to manually set that dom element as the el attribute when the view is initialized. Backbone provides you no shortcut for doing that.
I've experienced problems when passing values like ID and events in during construction as opposed to defining them during extension. You may want to check and see if that's the difference you're looking for.